rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P6222/2:b..l rcu: (detected by 0, t=10502 jiffies, g=8717, q=842 ncpus=2) task:syz.3.77 state:R running task stack:26008 pid:6222 tgid:6221 ppid:5817 task_flags:0x400140 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5256 [inline] __schedule+0x1139/0x6150 kernel/sched/core.c:6863 preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7190 irqentry_exit+0x1d8/0x8c0 kernel/entry/common.c:216 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:lock_release+0x183/0x2d0 kernel/locking/lockdep.c:5893 Code: 0f c1 05 28 00 19 12 83 f8 01 0f 85 03 01 00 00 9c 58 f6 c4 02 0f 85 ee 00 00 00 41 f7 c5 00 02 00 00 74 01 fb 48 8b 44 24 10 <65> 48 2b 05 bd b8 18 12 0f 85 32 01 00 00 48 83 c4 18 5b 41 5c 41 RSP: 0018:ffffc900059b7460 EFLAGS: 00000206 RAX: 2159fd860a9d3000 RBX: ffffffff8e3c96a0 RCX: ffffc900059b746c RDX: 0000000000000002 RSI: ffffffff8daa8a1d RDI: ffffffff8bf2b480 RBP: dffffc0000000000 R08: 0000000035e43d3a R09: 00000000a35e43d3 R10: 0000000000000002 R11: ffff88801ef50b30 R12: ffffffff823152c7 R13: 0000000000000206 R14: ffff88801ef50000 R15: 0000000000000003 rcu_lock_release include/linux/rcupdate.h:341 [inline] rcu_read_unlock+0x1c/0x60 include/linux/rcupdate.h:897 percpu_ref_tryget_many include/linux/percpu-refcount.h:250 [inline] percpu_ref_tryget include/linux/percpu-refcount.h:266 [inline] css_tryget include/linux/cgroup_refcnt.h:45 [inline] css_tryget include/linux/cgroup_refcnt.h:42 [inline] get_mem_cgroup_from_mm+0x2bb/0x600 mm/memcontrol.c:941 __mem_cgroup_charge+0x1a/0x1e0 mm/memcontrol.c:4744 mem_cgroup_charge include/linux/memcontrol.h:663 [inline] shmem_alloc_and_add_folio+0x50c/0xc20 mm/shmem.c:1942 shmem_get_folio_gfp+0x67f/0x1610 mm/shmem.c:2556 shmem_fault+0x1fe/0xa00 mm/shmem.c:2757 __do_fault+0x10d/0x490 mm/memory.c:5320 do_read_fault mm/memory.c:5755 [inline] do_fault+0xae4/0x1ad0 mm/memory.c:5889 do_pte_missing mm/memory.c:4401 [inline] handle_pte_fault mm/memory.c:6273 [inline] __handle_mm_fault+0x1919/0x2bb0 mm/memory.c:6411 handle_mm_fault+0x3fe/0xad0 mm/memory.c:6580 faultin_page mm/gup.c:1126 [inline] __get_user_pages+0x54e/0x3590 mm/gup.c:1428 populate_vma_page_range+0x267/0x3f0 mm/gup.c:1860 __mm_populate+0x1d8/0x380 mm/gup.c:1963 mm_populate include/linux/mm.h:3701 [inline] vm_mmap_pgoff+0x37f/0x470 mm/util.c:586 ksys_mmap_pgoff+0x7d/0x5c0 mm/mmap.c:604 __do_sys_mmap arch/x86/kernel/sys_x86_64.c:89 [inline] __se_sys_mmap arch/x86/kernel/sys_x86_64.c:82 [inline] __x64_sys_mmap+0x125/0x190 arch/x86/kernel/sys_x86_64.c:82 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f87f018f749 RSP: 002b:00007f87f104e038 EFLAGS: 00000246 ORIG_RAX: 0000000000000009 RAX: ffffffffffffffda RBX: 00007f87f03e5fa0 RCX: 00007f87f018f749 RDX: b635773f06ebbeee RSI: 0000000000b36000 RDI: 0000200000000000 RBP: 00007f87f0213f91 R08: ffffffffffffffff R09: 0000000000000000 R10: 0000000000008031 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f87f03e6038 R14: 00007f87f03e5fa0 R15: 00007ffc89698558 rcu: rcu_preempt kthread starved for 10530 jiffies! g8717 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->cpu=1 rcu: Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior. rcu: RCU grace-period kthread stack dump: task:rcu_preempt state:I stack:29104 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5256 [inline] __schedule+0x1139/0x6150 kernel/sched/core.c:6863 preempt_schedule_common+0x44/0xc0 kernel/sched/core.c:7047 preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline] _raw_spin_unlock_irqrestore+0x61/0x80 kernel/locking/spinlock.c:194 debug_object_assert_init+0x1c5/0x2f0 lib/debugobjects.c:1009 debug_timer_assert_init kernel/time/timer.c:803 [inline] debug_assert_init kernel/time/timer.c:848 [inline] __mod_timer+0xad/0xd30 kernel/time/timer.c:1025 add_timer+0x62/0x90 kernel/time/timer.c:1249 schedule_timeout+0x11e/0x290 kernel/time/sleep_timeout.c:98 rcu_gp_fqs_loop+0x1ea/0xaf0 kernel/rcu/tree.c:2083 rcu_gp_kthread+0x26d/0x380 kernel/rcu/tree.c:2285 kthread+0x3c5/0x780 kernel/kthread.c:463 ret_from_fork+0x983/0xb10 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 rcu: Stack dump where RCU GP kthread last ran: Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:82 Code: 86 5f 02 c3 cc cc cc cc 0f 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d 13 f9 11 00 fb f4 cc 35 03 00 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90 RSP: 0018:ffffc90000197de8 EFLAGS: 000002c6 RAX: 00000000002b6cf3 RBX: 0000000000000001 RCX: ffffffff8b7866d9 RDX: 0000000000000000 RSI: ffffffff8daceab2 RDI: ffffffff8bf2b480 RBP: ffffed1003b59498 R08: 0000000000000001 R09: ffffed10170a673d R10: ffff8880b85339eb R11: ffff88801dacaff0 R12: 0000000000000001 R13: ffff88801daca4c0 R14: ffffffff9088bdd0 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8881249f4000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000200000404030 CR3: 000000000e184000 CR4: 00000000003526f0 Call Trace: arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline] default_idle+0x13/0x20 arch/x86/kernel/process.c:767 default_idle_call+0x6c/0xb0 kernel/sched/idle.c:122 cpuidle_idle_call kernel/sched/idle.c:191 [inline] do_idle+0x38d/0x510 kernel/sched/idle.c:332 cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:430 start_secondary+0x21d/0x2d0 arch/x86/kernel/smpboot.c:312 common_startup_64+0x13e/0x148